Corn ears are showing tip loss, Northern corn leaf blight is persisting and Japanese Beetles are damaging corn and soybeans. Those are the highlights, or low lights if you prefer, of what I’ve seen scouting in the fields over the past few days.
Scout's Report 8/5: Corn and soybean insects make their move this week
Corn kernels are plump and leaves are green, corn has reached its prime time. Most ears around northern Indiana are showing R3 development, the milk stage. At this stage it’s very apparent the percentage of kernels that did not get pollinated.
Genetics and breeding selections in corn play a key role in the crop’s ability to produce kernels all the way through the tip of the ear.
Other factors affecting the completeness of fertilization include insect damage to silks, chemical damage during pollination stages and offset flowering dates between plants. Determining the average number of fertilized kernels on each ear can lead to a yield estimate for a field.
Keep in mind that brown silks cannot fertilize kernels, so damage at the green silk stage will limit yield while damaged brown silks will not. So insects chewing on brown silks is not a concern
Soybeans through the area have shown some signs of Sudden Death Syndrome. This is mainly due to the high moisture levels this year creating ideal environments for the growth of the fungus. The disease appears at first in smaller areas, usually compacted or more water logged parts of the field. Upper leaves will look yellow, turn to brown, shrivel and eventually die.
Certain varieties can be selected that are less likely for the major losses to occur. Talk to your local agronomist if you suspect SDS in your fields, and to select varieties for your next growing season.
Japanese Beetles have infested soybean fields in the state also. Leaves will show ragged holes in the top canopy, usually leaving behind larger veins with minimal tissue and small veins left. The yield damage for soybeans is usually not quantifiable and usually does not call for any treatment.
Scout's Report 7/29: UAVs, northern corn leaf blight and Japanese beetles
Sweep the soybeans 20 times, in five areas of a field to determine if their presence is approaching economics threshold. Refer to Purdue Extension for thresholds and information on insects.
The insect traps in north central Indiana had 7 ECB moths this week. That’s slowing down form peak capture. Look for my findings next week.
Kettler will be a junior in Purdue University Agronomy and Ag Economics this fall. She is an intern for Beck’s, supervised by Ben Grimme, Kris Johnson, Denny Cob and Steve Gauck. She writes from Atlanta.